The overall purpose of this investigation is to establish the mechanism(s) by which fibrous plaques develop. Our first goal in this investigation is to determine the levels and localization of prostaglandins in "normal" arteries and in the various lesions of atherosclerosis. Our second goal in this investigation is to study mechanisms by which prostaglandins may affect arterial wall metabolism. Our third goal is to characterize phospholipids in "normal" arteries and in the various lesions of atherosclerosis. Our fourth goal is to establish pathways for the biosynthesis of these phospholipids. Our fifth goal is to find an animal model with compositional changes in phospholipids similar to those in human tissues.